Door engine



' Patented Qct. 26; 1926.

UNITED STATES JOSEPH M. DAPRON, OF ST. LOUIS, MISSOURI, ASSIGNOR TO NATIONAL PNEUMATIC PATENT OFFICE.-

COMPANY, OF NEW YORK, N. Y., A. CORPORATION OF WEST VIRGINIA.

noon ENGINE.

Application filed December 15, 1923. Serial No. 681,022.

My invention relates to improvements in door engines and has for its object to provide a pneumatically operated engine for opening and closing car-doors and car-steps.

B The purpose of my construction is to provide an engine having a two-part cylinder and a single reciprocating piston mounted therein and arranged to exert its thrust or reverse movement directly upon a door-andstep control shaft; the piston being actuated V by compressed air admitted alternately to 1 the opposite ends of the cylinder, the piston ahaving a sleeve controlledshock-absorber.

Drawings.

In the drawings- Fig. 1 is a longitudinal horizontal midsectional view of an engine embodying my invention.

Fig. 2 is a side elevation of the same.

Description.

the projecting locks 7 and 8 respectively, se-

cured together by the bolts 9-9, or like fastoning means. The median slot 10 is formed as shown. extending from the meeting edges of the halves 3 and 4, so that when the cylinder A is assembled as shown in Fig. 2 said slot 10 serves as a guide for the piston arm 11 which is formed at the center of thepiston B, and is connected to the shaft 12 by the thrust-rod 13. The piston B is provided with concentric bores 14. in each of which is mounted a shock-absorbing mechanism'comprising a plunger 15 having a conoidal terminal 16, which terminal 16fhas a longitudinal grooved air-i ent 17 upon its tapering face. Within the bore 14 is a coil spring 18 upon whose outer end the inner disk terminal 19 of the plunger 15 rests.

The piston B has its terminals formed to produce the annular heads 20. the outer face of each of which is provided with the cupped Washer 21. Each of the heads 20 is provided with a screw-thread gasket 22, serving both as a hearing for the plunger 15, and

as a means for holding the cupped washer exerted upon a vertical shaft 12, which shaft serves to rest and lower the car-step, or open or close a car-step, or to perform all of said operations; said shaft B having the lever arm 23 connected to the piston arm 11 by the rod 13.

Assuming that the parts as illustrated in Fig. 1 represent the enginein door-closed position, and that it is desired to open the door, the operation is accomplished as fol.- lows: a

Air is admitted through the pipe 5 and strikes thevcupped Washer 21 with the initial effect of throwing the piston B to the right, and to a point where the connoidal right terminal 16 reaches its seat 24. This operation is rapid. the air in advance of the right hand piston head 20 being vented into atm os- 1 phere. The connoidal terminal 16 having reached its seat 24 closes the air space he hind it. forming an air cushion, which however is relieved by the vent 17 which provides for the gradual emission of air. during which process the right-hand pistonhead 20 has its progress checked by the action of the plunger 15 against the coiled spring 18.- Against this resistance, the right-hand piston head 20 continues to travel until it reaches the end of the cylinder A and the end of its stroke.

As various embodiments may. be made in in,2' sense.

Iclaim- A door engine comprising a cylinder 5 operating is said slot; each terminal of said 7 piston having a concentric bore provided with a spring and a plunger; each oi said plungers having a connoidal head arranged to seat in one of said valve-seats and provided with a grooved air-vent, as described. In testimony whereof I have hereunto afiix'ed my signature.

JOSEPH M. DAPRON. 

